1886.} 4J1 [Cope. 



y. Anal double. 



Scales keeled ; no loreal Leptop7ds* Bell. 



Scales keeled ; a loreal Sapsidophryg Fisch. 



Scales smooth ; a loreal Philothamuus\ Smith. 



yy m Anal single. 



Scales smooth ; a loreal ChloropMs\ Hallow. 



aa. A toothless space in front of the long maxillary tooth. 

 /?. One preocular ; anal double. 

 v. Form very elongate. 



A loreal ; scales smooth Uromacer D. & B. 



yy. Form moderately elongate. 



A loreal ; scales smooth, with two pits AlsopMs Cope. 



No loreal ; scales smooth Oeyophis% Cope. 



/5/3. Two or more preoculara. 

 Orbit resting on labials ; one loreal ; two anals ; two scale-pits 



Zamenis Wagl . 

 Orbit surrounded by scales ; anal single ; two scale-pits ; one loreal 



Periops Wagl. 

 Orbit surrounded by scales ; two or more loreals ; anal single ; two scale- 

 pits Ghilolepis | Cope. 



" Numerous small scales occupying the place of the frontals ;" eye resting 



on scales SpaleropJiis Jan. 



Orbit resting on labials ; two anals ; one scale-pit Tyria% Cope. 



One anal ; no scale-pits Zamenaphis Gthr. 



Philodryadin^. 



A. Body rounded, not compressed. 



a. Scales grooved. 

 Crown and lores grooved ; one nasal ; two loreals Malpolon** Fitz. 



aa. Scales smooth. » 



Two loreals ; middle teeth equal Callirlwius Gird. 



One loreal ; median teeth equal Philodryas Wagl. 



ODe loreal ; median maxillary teeth long Jaltris Cope. 



aaa. Scales keeled. 



One loreal ; median teeth equal Tropidodryas Cope. 



AA. Body slender, compressed. 



a. Subcaudal scutella. 



Nostril normal ; two nasals ; two anals Chrysopelea Boie. 



Nostril round in a single nasal ; two anals Ichihycyphua Gthr. 



Nostril semicircular, valvular Dromophis Pet. 



aa. Subcaudal scuta. 

 Anal divided Bucephalus Srn. 



* Ahcetulla Gthv. Thrasops Hallow. [ Type Coluber c.Uffordii Schl. 



t Rhamnophis Gthr. Gastropyxis Cope. ^Type T. clalilii Fitz. 



% Herpetcelhiops Gthr. ** Coslopeltis Wagl. Tapliromelopon 



I Type Dromicus ater Gosse. Brandt. 



PROC. AMER. FHILOS. SOC. XXIII. 124. oK. PRINTED NOV. 1, 1886. 



